JP2010251673A - Condensing element, condensing element group, and solid-state imaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure of a light condensing element which can be stably manufactured, even in a normal semiconductor device manufacturing step, and to prevent yield reduction and characteristic variations due to the shape variations in the light-condensing element. <P>SOLUTION: The light-condensing element has one or more first annular band regions 102. having a first refractive index and one or more second annular band regions 103 having a second refractive index different from the first refractive index; the first and second annular band regions 102 and 103 are arranged concentrically to be alternately adjacent to each other; and at least either of the first and second annular band regions 102 and 103 has a gap 104, at a section where the width of the annular band region becomes gradually narrow. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a condensing element, and in particular, a condensing element in which first and second annular zones having different refractive indexes are arranged concentrically and adjacently, a condensing element group, and The present invention relates to a solid-state imaging device.

  In general, a device that converts an image into an electric signal is used for an apparatus for electromagnetically recording an image such as a digital video recorder, a digital still camera, or a mobile phone with a camera that has been rapidly increasing recently. Called device). In recent years, charge coupled device sensors (generally referred to as CCD sensors; hereinafter referred to as CCD sensors) and MOS sensors, which are a kind of semiconductor elements, are used in imaging devices, and these devices are reduced in size and price. Contributing to These image pickup apparatuses constitute one screen by arranging a large number of minute pixels each including a single light detection element on a plane. Therefore, the performance of the imaging device is determined by the performance of these many pixels.

  Particularly important in the performance of imaging devices is the ability to convert minute input images into electrical signals with low noise (ie, low S / N ratio) and the ability to output input images with high electrical signals (ie, high amplification factor). is there.

  As a method for achieving a low S / N ratio and a high amplification factor, a method of improving the S / N ratio and the amplification factor of the photodetecting element in the pixel can be considered first, but the method described below is also generally adopted. The

  FIG. 19 is a diagram illustrating a cross section of one pixel in a conventional typical solid-state imaging device. As shown in the figure, the pixel 1601 includes a light detection element 1602, a light collection element 1603, a color filter 1604, and a wiring 1606. Incident light 1605 to the pixel 1601 is collected by the light collecting element 1603, separated into red, blue, or green by the color filter 1604 and then input to the light detecting element 1602. Since the intensity density of the incident light 1605 incident on the light detection element 1602 is increased by the condensing element 1603, it is possible to improve the low S / N ratio and the amplification factor.

  The problem here is that when the incident angle of the incident light 1605 changes, the focal point of the light condensing element 1603 also changes, and the light is not condensed on the light detecting element 1602. This is noticeable when the pixel 1601 is a peripheral pixel in the imaging device.

  In order to solve this problem, there is a conventional example in which light collecting elements are arranged asymmetrically with respect to each pixel (Patent Document 2). Alternatively, in the peripheral pixels of the imaging device, the position of the light detection element 1602 with respect to the light condensing element is conventionally shifted. However, in these conventional examples, the effect is high when the incident angle of the incident light 1605 is relatively small, but there is a problem that the effect is reduced when the incident angle is increased. Further, it is necessary to change the position of the wiring 1606 with respect to the light detection element 1602 in accordance with the angle of the incident light 1605. Usually, there is a restriction on the circuit arrangement position (layout rule), and this position change becomes impossible. There is also.

  In order to achieve the problem of maintaining the characteristics of the pixel even when the incident angle is large, in Patent Document 1, a condensing element is formed as shown in FIG. A pixel illustrated in FIG. 20A includes a plurality of annular light transmission films 1501, a substrate 1502, a light detection element 1504, and a wiring 1506. The light transmission film 1501 is processed into a circle or an annular shape having the same center. The width of the annular zone is about the wavelength of natural light or smaller, typically about 0.1 μm. The refractive index perceived by the incident light 1505 that passes through the light transmission film 1501 is a value averaged over a region of the order of the wavelength on the surface of the light transmission film 1501, and the refractive index or medium ( It is not typically the value of the refractive index of air). Since the width of the annular zone is extremely thin, the refractive index felt by the incident light 1505 depends on the width of the annular zone, and is an intermediate value between the refractive index of the light transmission film 1501 and the refractive index of the medium. In other words, the surface of the light transmission film 1501 is equivalent to the refractive index distributed concentrically for the incident light 1505. If this refractive index distribution is appropriately given, the incident light 1505 that has passed through the light transmission film 1501 and the substrate 1502 is condensed by the diffraction effect and reaches the light detection element 1502. The position where the incident light 1505 is collected can be controlled by changing the shape of the light transmission film 1501. Therefore, by designing the shape of the light transmission film 1501 in consideration of the incident angle of the incident light 1505, the light detection element 1502 can be focused without degrading the performance, and the above-described problem can be achieved.

  FIG.20 (b) is the figure which looked at Fig.20 (a) from the upper surface. Reference numeral 1501 denotes a light transmission film, and 1507 denotes a medium. The light transmission film 1501 and the medium 1507 are each in a ring shape and are arranged concentrically.

International Publication No. 2005/101067 JP 2001-196568 A

  However, if the shape of FIG. 20B is to be realized by a normal semiconductor device manufacturing process, the following problems occur.

  That is, the light transmission film 1501 and the medium 1507 are cut off along the outer periphery of a square shape (here, a square is used as an example, but a rectangle may be used in practice) as an area for one pixel.

  The minimum portion shown by 1508 is a problem in the cutting of the outer periphery. The width in the horizontal direction of the minimal portion 1508 may be infinitely small depending on the positional relationship between the outer periphery and the center of the light collecting element.

  The first problem is that lithography is used to produce a desired shape, but in lithography, the minimum size that can be produced is determined depending on the wavelength of the exposure light source, so an infinitely small structure cannot be realized. is there. Assuming that the horizontal width of the minimal portion 1508 is less than or equal to this minimum dimension, even if a mask pattern as shown in FIG. 20B is created and an exposure is attempted, the shape near the minimal portion 1508 is distorted or disappears. Just do it. That is, the shape as shown in FIG. 20B cannot be produced.

  As a second problem, in general, there is a certain variation in the shape and structure obtained in the normal semiconductor device manufacturing process. Appears or disappears and cannot be controlled either.

  For example, in the case of lithography, variations in the transfer shape after exposure occur due to variations in light intensity and unevenness and warpage of the upper surface of the wafer during exposure. For this reason, even if an attempt is made to produce a shape as shown in FIG. 20B, the shape of the minimal portion 1508 disappears or is distorted, and the shape varies greatly in any case.

  As described above, the condensing element disclosed in Patent Document 1 includes a structure such as the minimum portion 1508, and this portion cannot be stably manufactured in a normal semiconductor device manufacturing process. There's a problem. Since the shape changes greatly, process management becomes impossible, the yield decreases, and the characteristics of the light collecting element vary greatly.

  In view of the above problems, the present invention provides a condensing element, a condensing element group, and a solid-state imaging device that can be stably manufactured even in a normal semiconductor device manufacturing process and prevent yield reduction and characteristic variation due to variation in the shape of the condensing element. The purpose is to do.

  In order to solve the above-described problems, a light collecting element according to the present invention includes one or more first annular zones having a first refractive index and one having a second refractive index different from the first refractive index. A light condensing element having the above-described second annular zone, wherein the first annular zone and the second annular zone are arranged concentrically and alternately adjacent to each other. At least one of the first annular zone and the one or more second annular zones has a gap in a portion where the width of the annular zone is gradually narrowed.

  According to this configuration, since the first annular zone has the gap, it is possible to prevent the width of the first annular zone from being equal to or less than the minimum dimension that can be produced in the manufacturing process. Thereby, it is possible to prevent the shape of the first annular zone from being distorted or lost, and to prevent a decrease in yield and characteristic variations due to variation in the shape of the light collecting element. Further, a structure and shape that are too small to be controlled with respect to the amount of variation in the manufacturing process can be avoided, and the semiconductor device can be stably manufactured even in a normal semiconductor device manufacturing process.

  Here, at least one of the one or more first annular zones and the one or more second annular zones has a two-stage configuration, and the gap is a lower stage portion of the two-stage configuration. Or you may provide in the upper stage part.

Here, the opposing end faces of the gap may be substantially parallel.
Here, the one or more first annular zones are formed of a high refractive index material larger than air, the one or more second annular zones are made of air, and the one or more first zones are formed. At least one of the annular zones may have the gap, and the gap may be a gap and connected to the adjacent second annular zone.

  According to this configuration, the portion where the width of the first annular zone is gradually narrowed is replaced with a gap, and the above-described problem of preventing yield reduction and characteristic variation due to variation in the shape of the light collecting element is solved. To do.

  Here, the one or more first annular zones are made of a high refractive index material larger than air, the one or more second annular zones are made of air, and the one or more first zones are made of air. At least one of the two annular zones may have the gap, and the gap may be filled with the high refractive index material and connected to the adjacent first annular zone.

  According to this configuration, the gap in the portion where the width of the first annular zone is gradually narrowed is filled with the high refractive index material, and the yield reduction due to the variation in the shape of the condensing element and the characteristic variation are prevented. Solve the problem.

Here, the area of the gap may be 3% or less of the area of the light collecting element.
In addition, the light collecting element group of the present invention includes a first light collecting element that is the light collecting element described above, one or more first annular zones having a first refractive index, and a first refractive index. One or more second annular zones having different second refractive indexes, and the one or more first annular zones and the one or more second annular zones are concentric. And the second condensing element that is not adjacent to the first condensing element, and the first condensing element and the second condensing element are disposed adjacent to each other across a boundary. It may be.

  Here, the light collecting element group of the present invention includes at least two light collecting elements that are the above light collecting elements, and the length of the gap between the first light collecting elements is It may be different from the length of the gap of the second light collecting element.

  Here, the light collecting element group includes a plurality of the light collecting elements described above, and the length of the gaps in a predetermined number of the light collecting elements arranged in a line may change monotonously.

  Here, the light collecting element group includes a first light collecting element that is the light collecting element, one or more first annular zones having a first refractive index, and a first refractive index. One or more second annular zones having different second refractive indexes, and the one or more first annular zones and the one or more second annular zones are concentric. A second condensing element that is alternately adjacent to each other and does not have the gap, and the first condensing element and the second condensing element may be adjacent to each other. Good.

  Here, the length of the gap of the first light collecting element may be different from the length of the gap of the second light collecting element.

  Here, in the above-described light collecting element group, the length of the gaps in the predetermined number of light collecting elements arranged in a line may change monotonously.

  The solid-state imaging device of the present invention is a solid-state imaging device including an imaging region including a plurality of light receiving elements and a plurality of light collecting elements corresponding to the plurality of light receiving elements, wherein the plurality of light collecting elements are , Including the above-described condensing element.

  Here, the center position of the light collecting element has a deviation amount from the center position of the light receiving element, the deviation amount depends on the position in the imaging region of the light collecting element, and the length of the gap is You may depend on the position in the imaging area | region of the said condensing element.

  The condensing element in the present invention has the above-described configuration, can be stably manufactured even in a normal semiconductor device manufacturing process, prevents the shape of the first annular zone from being distorted or lost, and Yield reduction and characteristic variation due to variation in the shape of the light collecting element can be prevented.

It is a top view which shows the structure of the condensing element which concerns on Example 1 of this invention. It is the upper side figure of the condensing element which concerns on Example 1 of this invention, and sectional drawing of a pixel. It is a top view which shows the structure of the condensing element which concerns on Example 2 of this invention. It is a top view of the condensing element which concerns on Example 3 of this invention. It is a top view of the condensing element group which concerns on Example 4 of this invention. It is a figure which shows the condensing element which concerns on Example 5 of this invention. It is a figure which shows the condensing element group which concerns on Example 6 of this invention. It is a top view explaining the condensing element group which concerns on Example 7 of this invention. It is a top view of the condensing element which concerns on Example 8 of this invention. It is a figure which shows another example of the condensing element which concerns on Example 8 of this invention. It is a figure which shows the condensing element group which concerns on Example 9 of this invention. It is a figure which shows the condensing element group which concerns on Example 10 of this invention. It is a figure which shows the condensing element group which concerns on Example 11 of this invention. It is a figure explaining the condensing element group which concerns on Example 12 of this invention. It is the top view and sectional drawing of a condensing element and a pixel which concern on Example 13 of this invention. It is a figure explaining the manufacturing process of a 2 step | paragraph structure condensing element. It is a figure which shows the example of the 1st application with respect to several adjacent condensing elements. It is a figure which shows the 2nd example of application with respect to several adjacent condensing elements. It is sectional drawing of one pixel in the conventional typical solid-state imaging device. (A) It is sectional drawing of the condensing element in a prior art. (B) It is a top view of the condensing element in a prior art. It is a figure explaining the effect of Example 7 of this invention.

Embodiments according to the present invention will be described below.
The condensing element of the present invention includes one or more first annular zones having a first refractive index and one or more second annular zones having a second refractive index different from the first refractive index. The first annular zone region and the second annular zone region are arranged concentrically and alternately adjacent to each other. The widths of the first and second annular zones are about the wavelength of incident light or shorter. Thereby, the lens function of the condensing element is realized.

  In addition, at least one of the first annular zones or at least one of the second annular zones has a gap in a portion where the width of the annular zone is gradually narrowed. This gap prevents the width of the first annular zone from being less than the minimum size that can be produced in the manufacturing process. Further, the opposing end faces of the gap are substantially parallel. In other words, the gap has a shape in which a part is omitted substantially in parallel with the width direction of the annular zone. This shape can be easily formed by an existing manufacturing process.

  Hereinafter, specific embodiments will be described with reference to the drawings. In the following drawings, the same reference numerals represent the same components.

  In the first embodiment, the first annular zone region is formed of a high refractive index material larger than air, the second annular zone region is made of air, and the gap is a gap between adjacent second annular zone regions. The connected configuration will be described.

FIG. 1 is a top view showing the configuration of the light collecting element according to Embodiment 1 of the present invention. The condensing element in the figure is separated from other condensing elements adjacent to each other by a pixel end gap portion 101, and the in-pixel high refractive index portion 102 which is the second annular zone and the in-pixel which is the first annular zone. It has a gap 103 and a gap 104. The in-pixel gap portion 103 and the in-pixel high refractive index portion 102 are each substantially circular and are arranged concentrically. The center of the concentric circle may coincide with the pixel center or may not coincide (eccentric with respect to the pixel center). Here, the pixel end gap portion 101, the in-pixel gap portion 103, and the gap 104 are formed of a material having a refractive index lower than that of the in-pixel high refractive index portion 102 (hereinafter referred to as a low refractive index material). A typical combination of the low refractive index material and the material of the high refractive index portion 102 in the pixel is air and a silicon oxide film, respectively. Also, air and TiO ₂ may be used. Further, air and a silicon nitride film may be used. Further, a silicon oxide film and TiO ₂ may be used. Further, the present invention is not limited to these materials, and in principle, it is permissible if the refractive index of the low refractive index material is smaller than the refractive index of the material of the in-pixel high refractive index portion 102.

  FIG. 2 is a top view of the light-collecting element according to Example 1 of the present invention shown in FIG. 1 and a cross-sectional view of the pixel. The pixel 307 includes a light receiving unit 306, a light shielding film 305, and a light collecting element. The light shielding film 305. May also serve as wiring. The light receiving unit 306 is usually provided with a light detection element (generally a photodiode). In addition to these, other components such as color filters may be included. Thus, a pixel 307 is formed.

  A typical side length of the pixel 307 is about 6 μm to 1 μm. Further, the minimum width of the in-pixel gap 103 is about 0.1 μm. The same applies to the minimum width of the in-pixel high refractive index portion 102. The width of the pixel end gap 101 is about 0.1 μm to 1 μm. However, these minimum dimensions are dependent on the manufacturing apparatus (for example, depending on the exposure apparatus), and are not limited thereto. The minimum dimension shown here is a case where KrF is used as light for exposure. When a silicon oxide film is used as the high refractive index material and air is used as the low refractive index material, the thickness of the high refractive index portion 102 in the pixel (indicated by t in FIG. 2) is about 1.2 μm. is there. However, the present invention is not limited to this.

  In order to manufacture the condensing element according to the first embodiment of the present invention shown in FIGS. 1 and 2, for example, the following steps are possible. First, after the structure up to the lower surface of the light condensing element is produced by a general manufacturing process of the solid-state photodetecting element, a high refractive index thin film to be the basis of the in-pixel high refractive index portion 102 is laminated on the upper surface. . Next, a photoresist is laminated thereon, and exposed and developed by an exposure apparatus such as a scanner or a stepper. Thereafter, the high refractive index thin film is etched by means such as dry etching, and the photoresist is removed to complete. However, the manufacturing method is not limited to this.

  In FIG. 1, a gap 104 is arranged in the in-pixel high refractive index portion 102 in the vicinity where the in-pixel gap portion 103 approaches the pixel end gap portion 101. Due to the air gap 104, it is possible to prevent the width in the diameter direction of the high refractive index portion 102 in the pixel from being reduced to a size that cannot be manufactured in the semiconductor manufacturing process.

  In the first embodiment, an example in which a gap as a gap is provided in the first annular zone has been described. In the second embodiment, an example in which a gap is provided in the second annular zone will be described. In this case, the gap is filled with a high refractive index material and is connected to the adjacent first annular zone region.

  FIG. 3 is a top view showing the configuration of the light collecting element according to the second embodiment of the present invention. The condensing element of the figure is different from that of FIG. 1 in that it has a gap 203 instead of the gap 104. The gap 203 is convex outward from the center of the light collecting element and is formed of a high refractive index material. The in-pixel gap portion 103 and the in-pixel high refractive index portion 102 are each substantially circular and are arranged concentrically. The center of the concentric circle may coincide with the pixel center or may not coincide (eccentric with respect to the pixel center). The material, dimensions, manufacturing method, and the like are the same as those in the first embodiment.

  In FIG. 3, a gap 203 filled with a high refractive index material is disposed in the vicinity of the intra-pixel high refractive index portion 102 close to the pixel end in the region of the intra-pixel void portion 103. By disposing the gap 203, it is possible to avoid that the width in the diameter direction of the in-pixel gap portion 103 becomes small and cannot be produced in the semiconductor manufacturing process.

  FIG. 4 shows a top view of a light collecting element according to Example 3 of the present invention. In the same figure, the in-pixel void portion 103 and the in-pixel high refractive index portion 102 are each substantially circular and arranged concentrically.

  In FIG. 4, the concentric circle center is shifted in an oblique direction with respect to the pixel center. In this case, if the two gaps 104 are arranged as shown in FIG. 4, it can be avoided that the gap 104 becomes too small to be manufactured in the semiconductor manufacturing process.

  FIG. 5 shows a top view of a condensing element group according to Embodiment 4 of the present invention. In FIG. 5, the light condensing element mounted on the left pixel does not have the gap 104, but the light condensing element mounted on the right pixel has the air gap 104. This is because the concentric circle center is located at a position relatively close to the pixel center in the condensing element mounted on the left pixel, but the concentric center is located at a position relatively distant from the pixel center in the condensing element mounted on the right pixel. Because there is. As described above, when the center position of the concentric circle changes for each pixel, whether or not the air gap 104 is to be installed can be manufactured stably and with a high yield by determining as follows.

Paying attention to the distance d shown in FIG.
d <k1λ / NA
If this is satisfied, the air gap 104 may be disposed at this position. Here, NA is the numerical aperture of the exposure apparatus, λ is the exposure wavelength, and k1 is a proportional coefficient. When a KrF scanner is used as the exposure apparatus and a phase shift mask is used, the right side is about 0.1 μm.

  If this is ignored and the gap 104 is not arranged even though the above equation is satisfied, resist bridging or disappearance occurs at this portion, and it becomes impossible to manufacture practically. Actually, it is better to determine the minimum dimension of d with a margin than the above formula. When a KrF scanner is used, we have found that a light collecting element can be stably manufactured when the thickness is about 0.2 μm.

  As a point of caution, if the gap 104 becomes too large, there is an effect such as deterioration of the characteristics of the light collecting element due to the addition of the gap 104. Therefore, the area of the gap 104 is limited to about 3% or less with respect to the pixel area. It is desirable to keep it.

  FIG. 6 shows a condensing element according to Example 5 of the present invention. In this embodiment, the center of the concentric circle is obliquely displaced with respect to the center of the pixel, so that two gaps 104 need to be arranged. Others are the same as in Example 4.

  FIG. 7 shows a condensing element group according to Example 6 of the present invention. FIG. 7 shows a part of a plurality of condensing elements according to the present invention arranged on an actual solid-state image sensor. In general, a solid-state imaging device has a structure in which pixels are two-dimensionally arranged, and a condensing element is mounted on the top of each pixel. In a general camera system, an optical lens for imaging is further arranged on the upper side of the solid-state image sensor, and an image from the outside to be imaged is projected onto the solid-state image sensor. Since this projection image has a spread, the chief ray angle of the incident light on each pixel changes depending on the position of the pixel. In other words, the angle of the incident light to the pixel located at the center on the solid-state light detection element is perpendicular to the solid-state light detection element, but the incident light becomes oblique as the position moves from there to the periphery of the solid-state light detection element. To go. Correspondingly, the center position of the condensing element is gradually changed so that incident light is guided to the light receiving surface in each pixel.

  At this time, by gradually changing the widths of the gaps 104a, 104b, and 104c as the center position gradually changes, it is possible to manufacture stably without deteriorating the characteristics of the light collecting element.

  Here, although the condensing elements adjacent in the horizontal direction are shown, the same applies to the case where they are adjacent in the vertical direction and the case where they are adjacent in the oblique direction.

  Note that the above-described solid-state imaging device is not limited to having a function of capturing a still image or a moving image, but may have a light detection function of simply detecting the presence or absence of light or a change.

  FIG. 8 is a top view for explaining a condensing element group according to Embodiment 7 of the present invention. Here, a condensing element for four pixels is shown. In the light condensing element arranged in each pixel in the figure, the in-pixel void portion 103 and the in-pixel high refractive index portion 102 are each substantially circular and arranged concentrically. In FIG. 8A, the gap 104a is arranged as described in the sixth embodiment. That is, the width of the gap 104 increases as it goes to the right, 104a, 104b, 104c. On the other hand, in FIG. 8B, the arrangement is almost the same as FIG. 8A, but the width of the gap 104 does not necessarily increase as it goes to the right. However, the width of the gap 104f is larger than that of the gap 104d. When the four pixels in FIG. 8B are viewed globally, it can be said that the width is increased in the right direction as in FIG. 8A. In this way, even if the gap width does not change monotonically locally, if it changes monotonically globally, that is, the length of the gaps in a predetermined number of the light-collecting elements arranged in a row is monotonous. If this is changed, the same effect as in the sixth embodiment can be obtained. However, if the arrangement method of the gap described in the sixth embodiment and the arrangement method of the seventh embodiment are significantly different, it is necessary to pay attention because unevenness and noise are superimposed on the output image from the solid-state imaging device. is there.

  FIG. 21 is a diagram for explaining the effect of the invention of the light collecting element group according to Example 7 of the invention. When the size of the condensing element is 5.6 μm square and the minimum size of the gap 104 is 200 μm wide and 150 μm long, the change in signal intensity at each pixel is shown. The horizontal axis is the pixel position, and the coordinates when moving from the center to the outside on the solid-state imaging device are shown in units of pixels. The vertical axis represents the signal intensity, but is normalized by the pixel signal intensity at coordinate 0.

  For example, let us consider a case where the signal intensity decreases linearly as shown in FIG. When the present invention is applied to this, a signal intensity discontinuous change occurs before and after the introduction of the air gap 104. However, when the gap 104 is made sufficiently small, this discontinuous amount can be made so small that it cannot be confirmed on the output image (in this case, less than about 1%). On the other hand, when the present invention is not applied, the shape is expected to be unstable, so that the characteristics are not monotonous as shown in FIG. This can be confirmed as rough in the output image.

  FIG. 9 shows a top view of a condensing element according to Embodiment 8 of the present invention. The in-pixel gap portion 103 and the in-pixel high refractive index portion 102 are each substantially circular and are arranged concentrically.

  In FIG. 9, the center of the concentric circle is shifted obliquely with respect to the pixel center. In this case, if a gap 203 filled with two high refractive index materials is arranged as shown in FIG. 9, it is possible to avoid a size that cannot be manufactured in the semiconductor manufacturing process.

  FIG. 10 shows another example of the light collecting element according to the eighth embodiment of the present invention. The in-pixel gap portion 103 and the in-pixel high refractive index portion 102 are each substantially circular and are arranged concentrically. In the condensing element of FIG. 10, the gap 203 filled with the high refractive index material in the pixel is in contact with the upper, lower, left, and right pixel boundaries, and therefore, the gap 203 filled with the high refractive index material is arranged at four positions on the upper, lower, left, and right. Yes. Various shapes of condensing elements other than those shown in FIGS. 9 and 10 are conceivable. However, if the gap 203 filled with a high refractive index material is disposed in the same way, the size cannot be produced in the semiconductor manufacturing process. Can be avoided.

  FIG. 11 shows a condensing element group according to Example 9 of the present invention. The in-pixel gap portion 103 and the in-pixel high refractive index portion 102 are each substantially circular and are arranged concentrically.

  In FIG. 11, the condensing element mounted on the left pixel does not have the gap 203 filled with the high refractive index material, but the condensing element mounted on the right pixel has the gap 203 filled with the high refractive index material. . This is because the concentric circle center is located at a position relatively close to the pixel center in the condensing element mounted on the left pixel, but the concentric center is located at a position relatively distant from the pixel center in the condensing element mounted on the right pixel. Because there is. As described above, when the concentric circle center position changes for each pixel, whether or not the gap 203 filled with the high refractive index material is to be installed is determined as follows. The device can be manufactured as in Example 4.

  FIG. 12 shows a condensing element group according to Example 10 of the present invention. The in-pixel gap portion 103 and the in-pixel high refractive index portion 102 are each substantially circular and are arranged concentrically.

  In this embodiment, since the center of the concentric circle is obliquely displaced with respect to the pixel center, it is necessary to arrange two gaps 203 filled with the high refractive index material. Others are the same as in Example 9.

  FIG. 13 shows a condensing element group according to Example 11 of the present invention. Here, condensing elements for four adjacent pixels are shown. In the light condensing element arranged in each pixel, the in-pixel void portion 103 and the in-pixel high refractive index portion 102 are each substantially circular and arranged concentrically.

  Similarly to the sixth embodiment, if the widths of the gaps 203a, 203b, 203c filled with the high refractive index material are gradually changed, the light collecting element can be stably manufactured without deteriorating the characteristics.

  FIG. 14 is a view for explaining a condensing element group according to Embodiment 12 of the present invention. Here, a condensing element for four pixels is shown. In the light condensing element arranged in each pixel in the drawing, FIG. 14A shows gaps 203a, 203b, 203c filled with a high refractive index material as described in the eleventh embodiment. . That is, the width decreases as the gaps 203a, 203b, 203c filled with the high refractive index material go to the right. On the other hand, in FIG. 14B, the arrangement is almost the same as in FIG. 14A, but the widths of the gaps 203d, 203e, 203f filled with the high refractive index material are not necessarily reduced toward the right. However, the gap 203f filled with the high refractive index material has a smaller width than 203d. When the four pixels in FIG. 14 (b) are viewed globally, the width is the right as in FIG. 14 (a). In other words, the length of the gap 203 in the predetermined number of the light-collecting elements arranged in a row is monotonously reduced. As described above, even if the width of the gap 203 does not change monotonically locally, the same effect as that of the eleventh embodiment can be obtained as long as the gap 203 changes monotonically. However, if the arrangement method of the air gap described in the eleventh embodiment and the arrangement method of the twelfth embodiment are significantly different, care must be taken because unevenness and noise are superimposed on the output image from the solid-state imaging device. is there.

  FIG. 15 is a top view and cross-sectional view of a pixel having a condensing element according to Embodiment 13 of the present invention. The light collecting element of FIG. 15 has a two-stage configuration, and is different from FIGS. 1 and 2 in that an upper pixel high refractive index portion 1701 is added.

  Before describing Example 13 of the present invention, a method for manufacturing the two-stage condensing element shown in FIG. 15 will be described. FIG. 16 is a diagram for explaining a method of manufacturing a two-stage condensing element. The process proceeds in order from (a) to (e). FIGS. 4A to 4E each show a cross section of one pixel of a solid-state imaging device including a light shielding film and a light receiving element. 2002 is a light collecting element before completion, and is processed as the process proceeds from (a) to (e). Reference numeral 2003 denotes a first mask, 2003a denotes a light shielding portion of the first mask, and 2003b denotes a light transmission portion of the first mask. Reference numeral 2004 denotes a resist. Reference numeral 2005 denotes a second mask, reference numeral 2005a denotes a light shielding portion of the second mask, and reference numeral 2005b denotes a light transmission portion of the second mask.

  FIG. 16A shows the condensing element 2002 before processing. The material of the light collecting element 2002 is typically a silicon oxide film, and the thickness is about 0.8 μm to 1.5 μm. A resist is applied to the upper surface of the light condensing element 2002 in FIG. 16A, and exposure is performed using the first mask 2003. If the resist is a positive type, after development, the resist shape disappears in a portion corresponding to the light transmission portion 2003b of the first mask as shown in 2004 of FIG. 16B, and the light shielding portion 2003a of the first mask disappears. The corresponding part remains.

  In the state of FIG. 16B, after etching all the thickness of the light collecting element 2002 using a method in which the etching rate of the material of the light collecting element 2002 is sufficiently larger than the etching rate of the resist, the resist is removed. For example, a shape as shown in FIG.

  Next, if a resist is applied to the upper surface of FIG. 16C and exposed and developed with the second mask 2005, the shape of FIG. 16D is obtained. Then, if the condensing element 2002 is partially etched by a predetermined thickness, the final shape of FIG. 16E is obtained. The etching depth at this time is typically about one-fourth to one-third of the thickness of the light collecting element 2002.

  If a method similar to the light collecting element described in the first to the twelfth embodiments of the present invention is applied to the light collecting element having such a two-stage configuration, the yield due to the variation in the shape of the light collecting element. It is possible to solve the problem of preventing deterioration and characteristic variation.

Hereinafter, some application examples of the two-stage condensing element will be described.
FIG. 17 shows a first application example of several adjacent light collecting elements. An intra-pixel high refractive index portion 151 is provided in the upper stage of the lower intra-pixel high refractive index portion 102. The lower intra-pixel high refractive index portion 102 has a lower air gap 104. The light collecting element shown in FIG. 17 is applied to the lower in-pixel high refractive index portion 102 as in the light collecting element according to Example 1 of the present invention.

  FIG. 18 shows a second application example for several adjacent light collecting elements. An intra-pixel high refractive index portion 151 is provided in the upper stage of the lower intra-pixel high refractive index portion 102. The upper pixel high refractive index portion 151 in the upper stage has an upper gap 104. In the condensing element shown in FIG. 18, the method shown in the condensing element according to Example 1 of the present invention is applied to the upper in-pixel high refractive index portion 151.

  The condensing element in the present invention can be used for a solid-state imaging device and is useful. Moreover, it is useful for a condensing element having a fine concentric shape.

101 Pixel end gap 102, 1701 In-pixel high refractive index portion 103 In-pixel gap portion 104 Gap 203 Gap 305 Light-shielding film 306 Light-receiving portion 307 Pixel 1501 Light transmission film 1502 Substrate 1503 Color filter 1504 Photodetecting element 1505 Incident light 1506 Wiring 1507 Medium 1508 Minimal part 2001 Solid-state imaging device 2002 Condensing element 2003 First mask 2004 Resist 2005 Second mask

Claims (14)

One or more first annular zones having a first refractive index and one or more second annular zones having a second refractive index different from the first refractive index; 1 is a light collecting element in which the annular zone region and the second annular zone region are arranged concentrically and alternately adjacent to each other,
At least one of the one or more first annular zones and the one or more second annular zones is a condensing element having a gap in a portion where the width of the annular zone is gradually narrowed. At least one of the one or more first annular zones and the one or more second annular zones has a two-stage configuration,
The condensing element according to claim 1, wherein the gap is provided in a lower stage or an upper stage of the two-stage configuration.   The condensing element according to claim 1, wherein the opposing end faces of the gap are substantially parallel. The one or more first annular zones are formed of a high refractive index material larger than air;
The one or more second annular zones are constituted by air;
At least one of the one or more first annular zones has the gap,
The light collecting element according to claim 1, wherein the gap is a gap and is connected to an adjacent second annular zone region. The one or more first annular zones are formed of a high refractive index material larger than air;
The one or more second annular zones are constituted by air;
At least one of the one or more second annular zones has the gap,
The condensing element according to claim 1, wherein the gap is filled with the high refractive index material and is connected to an adjacent first annular zone region. The condensing element according to claim 1, wherein an area of the gap is 3% or less of an area of the condensing element. A first light collecting element which is the light collecting element according to claim 4;
One or more first annular zones having a first refractive index, and one or more second annular zones having a second refractive index different from the first refractive index, Two or more first annular zones and the one or more second annular zones are arranged concentrically and alternately adjacent to each other, and have a second light collecting element without the gap,
The said 1st condensing element and the 2nd condensing element are the condensing element groups arrange | positioned adjacent on both sides of the boundary. A first light collecting element which is the light collecting element according to claim 4;
A second light collecting element which is the light collecting element according to claim 4,
The length of the gap between the first light collecting elements is different from the length of the gap between the second light collecting elements. A plurality of light collecting elements according to claim 4,
A condensing element group in which the length of the gap in a predetermined number of the condensing elements arranged in a row changes monotonously. A first light collecting element which is the light collecting element according to claim 5;
One or more first annular zones having a first refractive index, and one or more second annular zones having a second refractive index different from the first refractive index, Two or more first annular zones and the one or more second annular zones are arranged concentrically and alternately adjacent to each other, and have a second light collecting element without the gap,
The said 1st condensing element and the 2nd condensing element are condensing element groups arrange | positioned adjacently. A first light collecting element which is the light collecting element according to claim 5;
A second condensing element that is the condensing element according to claim 5,
The length of the gap between the first light collecting elements is a light collecting element group different from the length of the gap between the second light collecting elements. A plurality of light collecting elements according to claim 5 are provided,
A condensing element group in which the length of the gap in a predetermined number of the condensing elements arranged in a row changes monotonously. A solid-state imaging device including an imaging region including a plurality of light receiving elements, and a plurality of condensing elements corresponding to the plurality of light receiving elements,
The solid-state imaging device including the condensing element according to claim 1, wherein the plurality of condensing elements. The center position of the light collecting element has a deviation amount from the center position of the light receiving element,
The amount of deviation depends on the position of the light collecting element in the imaging region,
The solid-state imaging device according to claim 13, wherein a length of the gap depends on a position of the light collecting element in an imaging region.

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